setAnimationSpeed = value => {
  alert("调整播放速度");
  alert(parent.timespan);
  // range of value [1, 100]
  value = parseInt(value)
  if (value >=1 && value<=100 ) {
    const min = 5;
    const max = 50;
    alert(timespan);
    timespan = parseInt(1.0*value/100*(max-min)+min);
    alert(timespan);
  }
}